[HWYSTR455]

You will get a lot of varying opinions on springs, but the 'norm' for many spring suppliers is a variance of rate +- 10% or more.

I would have to recommend Global West, as I always do, and you have to call Doug and talk to him. He doesn't advertise rates for his springs, which is why you have to call. If he doesn't nail what you're looking for, he will swap them out for free. Not many if any do that anymore.

Don't believe for a min that those who claim they make springs to 'factory specs', because it is not true. For one, many of the specs are wrong, and as parts start getting grouped together to 'work' across multiple platforms, it strays even further from the target.

The best spring manufacturers provide a rate testing curve results for the springs you order, with all the specs. And not just a photocopied image.

Instead of me going back through the thread, are you going 'factory stock', with OE control arms and bushings?



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[HWYSTR455]

Eaton's tolerance is +- 10%.

If you order a pair of springs that are for example 400lbs, and the pair you get, one is at the one end of the tolerance (40lbs), and the other end of tolerance, there can be a 80lbs difference from side to side.

Landrum' tolerance is +- 2% - 3%. But, you need to know exactly what you want.

https://landrumspring.com/leaf-sprin...l-information/

If you have a free-articulating suspension, what you want is different than a stock bushing suspension. (one simple example)


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[72projectbird]

Originally Posted by Formulabruce

If you'll use new, the Eaton with the 1 inch drop seem like the right height. I would NOT get the highest spring rating either. Keep in mind these cars ALL sat " about " and inch higher in the front in Stock form due to weight in front.
Never get generic springs for 67-81 camaro nova big block.

Nope, no generic springs for me. I'll look into Eaton springs.

Originally Posted by HWYSTR455

Instead of me going back through the thread, are you going 'factory stock', with OE control arms and bushings?

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Going all original, even using the original spiral shocks.

[HWYSTR455]

The issue with replacement rubber bushings is that Pontiac used a specific durometer rubber, matched to the spring. All the 'replacement' control arm bushings are not of the same rating.

So if you use your standard Moog replacement lower control arm bushing, to compensate for the softer bushings, you have to use a higher rate spring to make up the difference.

Later years for example t he WS6 cars, they used a higher durometer bushing than the 'standard' suspensions.

Of course if all you are concerned with is a 'factory appearance', then it won't matter, basically as long as the ride height is factory appearing, no one will know the difference. (until you drive it).



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[Formulabruce]

Originally Posted by HWYSTR455

The issue with replacement rubber bushings is that Pontiac used a specific durometer rubber, matched to the spring. All the 'replacement' control arm bushings are not of the same rating.

So if you use your standard Moog replacement lower control arm bushing, to compensate for the softer bushings, you have to use a higher rate spring to make up the difference.

Later years for example t he WS6 cars, they used a higher durometer bushing than the 'standard' suspensions.

Of course if all you are concerned with is a 'factory appearance', then it won't matter, basically as long as the ride height is factory appearing, no one will know the difference. (until you drive it).



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Well said, And there are many ways to make stock looking suspension to ride better., handle better.
Nearly ALL the new rubber is GMO rubber and deteriorates much faster than the originals.

[Formulabruce]

Dave, I believe I have a NOS set of rear subframe bushings. they say Chevrolet on them as both used same bushing.

[HWYSTR455]

GMO rubber, that's funny! Heheh!


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[72projectbird]

Subframe in first round of bodywork and primer. Fixed the sway bar mounting points. It's getting pretty smooth!

[72projectbird]

A little dash of color!